A. Field of the Invention
The field of the present invention relates generally to mechanical harvesters for use in harvesting crops. More specifically, the present invention relates to such harvesters that move along the ground and are particularly useful for harvesting of tree-borne crops grown in rows of trees. Even more specifically, the present invention relates to such mechanical harvesters that utilize a plurality of oscillating rods to separate the crop from the tree and are particularly beneficial for harvesting pomegranates, citrus and the like.
B. Background
The growing of pomegranate trees and the harvesting of its fruit originated in area of ancient Persia and spread through out the Mediterranean and Black Sea regions, where it has been cultivated for several millennia. From there, cultivation of the pomegranate spread throughout India and the drier parts of Asia, East Indies and Africa. Spanish colonist introduced the pomegranate to the Caribbean, Latin America and, in approximately 1769, California. In the United States, the pomegranate is primarily grown for its fruit in the drier parts of California and Arizona. Although pomegranates have been grown as a source of food, for ornamental purposes and for religious purposes for many thousands of years, only recently has the popularity of the fruit substantially increased and, as a result, the fruit is now widely distributed. The primary reason for the upsurge in popularity of pomegranates, generally as a juice or juice extract, has to do with its health benefits. Recent studies indicate that pomegranate fruit is a good source of vitamins, particularly vitamin C and B5, potassium and antioxidants and that it can reduce heart disease risk factors and lower blood pressure. Other studies indicate pomegranate juice may reduce the likelihood of certain cancers and diabetes and that it has potential antiviral and antibacterial benefits. As a result of the demand for pomegranate juice and for products having pomegranate as an ingredient, there has been a substantial increase in pomegranate planting and harvesting.
The pomegranate tree, which is in the form of a large, generally rounded shrub-like small tree, typically grows twelve to sixteen feet in height with one or more trunks that produce limbs from which extend secondary laterals that are generally stiff and very spiny. The pomegranate fruit grows directly from the secondary laterals. As well known, the pomegranate fruit is not easily separated from the secondary lateral. Because of this, and the fact that the pomegranate tree trunk is not very strong, shaking the trunk (like is done for many varieties of nuts) or the tree generally is not a useful method of harvesting pomegranates. In fact, due to the difficulties of separating the fruit from the tree, presently there is no machine for or mechanical method of harvesting pomegranates. Instead, the conventional method of harvesting pomegranates is very labor intensive. As a result, to grow and harvest pomegranates in a large scale, commercial manner requires a significant number of laborers to separate the crop from the tree. The present method of harvesting pomegranates requires laborers to walk through the rows of trees, reach inside a tree to grasp an individual fruit and then pull on the fruit to separate it from the tree. Due to the thorns and the difficulty in separating the stem from the laterals, this is a time consuming and costly process for the grower and potentially painful for the laborer. As well known in the agricultural industry, there are many issues with regard to the availability of laborers, many of whom have traditionally been in this country illegally or otherwise without proper documentation, and the cost of paying those laborers. As with many crops, it is generally necessary to have a large number of skilled workers available at the time when the pomegranates are ready to be harvested. If they are not available when needed, the crop may be lost. As a result, the cost and availability of labor for pomegranate harvesting threatens to limit the ability to grow pomegranates on a large scale, commercially viable manner.
Harvesting of citrus as many of the same attributes and issues as identified above for pomegranates. One difference with regard to the mechanical harvesting of citrus, particularly oranges, is that care must be taken to separate the fruit from the tree to avoid causing the stem to pull the cap off of the skin and, thereby, leave a hole into the fruit. As a result of this problem, mechanical harvesting of citrus is primarily done for fruit that is harvested for the juice market or when it is necessary to remove fruit that has been damaged by a freeze or other event. For certain fresh fruit markets, some people may be willing to accept the cap removal damage done to the fruit by mechanical harvesting in exchange for the cost savings attributable to mechanical harvesting. In addition, over time certain fruit trees may be genetically modified to provide fruit that does not remove the cap of the skin when separated from the tree.
As well known to those skilled in the art, many different types of mechanical harvesters have been developed to harvest fruit. Due to various limitations and problems, very few of these machines are commercially available or in use by growers. A successful mechanical harvesting machine for harvesting fruit from trees must be able to efficiently and effectively move to and about the orchard from which the fruit will be harvested, move from one tree to another tree and move from one row of trees to another row. The harvesting machine must also be able to harvest the fruit from substantially the entire tree, including the top, bottom and middle of the tree, in order to avoid having to hand pick much, if any, of the remaining fruit on the tree. The harvesting machine must also be configured to not damage the tree, including breakage of limbs and trunks, or the fruit, as applicable, that is removed from tree. Preferably, a harvesting machine for picking fruit from trees will be able to move along a row of trees and harvest fruit from each tree while stopping for as short of time as possible at the tree so as to limit the amount of time required for harvesting to as little as possible.
Over the years, various attempts have been made to provide a harvesting machine to mechanically harvest citrus. For instance, U.S. Pat. No. 3,485,025 to Bohannon describes a mechanical citrus fruit harvester having a harvesting head mounted on a support platform with a plurality of harvesting fingers projecting from the harvesting head that are vibrated vertically and horizontally to engage and remove fruit from within a tree. A telescoping chute transfers the removed fruit to a conveyor mechanism that transfers the fruit to a bin or other container. U.S. Pat. No. 5,666,795 to Wilkinson describes a citrus harvesting machine having a plurality of outwardly extending picking arms carried on a driver bar that is moved toward and away from the tree so the picking arms may selectively penetrate the tree canopy. The picking arms have a generally hook-shaped picking member at their distal end that separates the fruit from the branch during retraction of the picking arms. A drive mechanism applies a cyclic motion to the individual picking arms to assist in dislodging the fruit from the tree. A more recent mechanical citrus harvesting machine, available from Oxbo Corp., is a continuous travel canopy shaker that has a plurality of outward extending tines disposed in a generally circular pattern which are inserted into one side of the tree's canopy and then shaken to dislodge the fruit from the tree. A pair of the machines are moved along the open spaces on either side of a row of trees to remove fruit from trees in the row by rapidly shaking the tines inside the canopy. A number of workers, such as 25 to 30, follow behind the harvester to collect the fruit that is knocked onto the ground by the harvester.
Despite the foregoing, what is needed is a harvesting machine and method of harvesting that effectively separates pomegranate and citrus fruit from the tree without damaging the tree or the fruit so that the pomegranates and citrus can be harvested in a more commercially acceptable and efficient manner. A desirable harvesting machine and method is one that is particularly beneficial for harvesting crops grown on trees having crops, such as pomegranates, that are generally difficult to remove by hand and cannot be safely, efficiently or effectively removed by shaking the trunk of the tree. Preferably, a harvesting machine and method would allow harvesting of the crop to take place as quickly and efficiently as possible with a low number of laborers and less wasted time and effort so as to facilitate the commercial cultivation of pomegranates and citrus by reducing the overall cost of such harvesting. The desired harvester and method of harvesting should be able to harvest virtually all or the vast majority of the crop off of the tree in order to reduce the need for follow-up hand harvesting. The preferred harvester and method of harvesting should substantially eliminate the need to collect fruit off of the ground.